Research On The Equipment And Process Of Friction Pull Plug Welding For On-site Manufacturing

In many complicated processes of aerospace equipment production,welding technology will directly affect its quality and use.Only scientific and complete welding processes can guarantee high quality welds,so that aerospace equipment can have higher quality.The use of the friction pull plug welding is used for the repair welding of the welding defects at the bottom of the outer space of the space shuttle,which improves the production efficiency of the outer tank and the reliability of the work of the outer tank.At present,there is a lack of the friction welding equipment that can be applied to the field,and at present,the optimization of the process parameters of the friction plug welding is mostly carried out through experiments,and the corresponding theoretical mechanical model is lacking.Therefore,this paper has studied it from the following aspects.(1)The robotic friction pull plug welding system was introduced,and then the friction plug welding equipment was designed.The preliminary design and application requirements analysis of the support frame,support structure and plug joint structure of the plug welding spindle were mainly carried out.Finally,the parameters of the selected robot body are described.(2)Based on the analysis of the friction pull plug welding process,a mechanical analytical model of the friction pull plug welding is established.The mechanical analysis model is used to describe the torque,axial force,power and energy of the plug during the welding process.Based on the heat generation model of the plug is equal to the endothermic model of the workpiece,and the energy conservation equation of the plug welding process is established.Based on the sensitivity analysis of the rotational speed,the plug angle and the feed rate parameters,the trend of each index value with the design variables is obtained.The higher the speed,the larger the taper angle,the greater the feed rate,the smaller the energy,the greater the material extrusion rate.(3)The four-leg support mechanism for the friction pull plug welding equipment has a small opening and a weak rigidity.The four-leg support mechanism is topology-optimized and optimized to be a three-leg support mechanism.The static analysis and modal analysis of the four-leg support mechanism and the three-leg support mechanism were carried out respectively.After analysis,the three-leg support mechanism is more suitable for the working conditions of the welding site than the four-leg support mechanism.(4)The DEFORM-3D software was used to simulate the process of the friction pull plug welding and the analysis of metal flow models.The mechanical process of the friction pull plug welding was analyzed and the plasticity was analyzed by introducing the 3D model established in CREO into the DEFROM-3D software.By Comparing the simulation analysis of sensitivity with the theoretical calculation,the error between simulation and theory is less than 25%.Then,the friction pull plug welding process test was carried out on the self-developed equipment,and the torque,axial force,power and energy curves of the plug welding process were obtained through the friction pull plug welding process test.In comparison,the error between the test and the theory is less than 7.2%..The theoretical mechanics model established in this paper is verified by simulation and experiment.